Some packages test for CMAKE_SYSTEM explicitly[1]
CMAKE_SYSTEM is comprised of CMAKE_SYSTEM_NAME and CMAKE_SYSTEM_VERSION.
It defaults to CMAKE_SYSTEM_NAME if CMAKE_SYSTEM_VERSION is not set[2]
At the point CMAKE_SYSTEM_NAME is set to "Linux" CMAKE_SYSTEM is already
constructed. Setting it explicitly ensures that it is the correct value.
This is because we do set CMAKE_SYSTEM_NAME twice, in fact:
- first in toolchainfile.cmake, so that we tell cmake to use the
"Buildroot" platform,
- second, in the Buildroot.cmake platform definition itself, so that
we eventually behave like the Linux platform.
We also set CMAKE_SYSTEM_VERSION to 1, and so the real CMAKE_SYSTEM
value should be set to Linux-1 if we were to follow the documentation to
the letter.
However, for Linux, the version does not matter, and in some situations
may even be harmful (that was reported in one of the commits that
introduce Buildroot.cmake and toolchainfile.cmake).
[1] Fluidsynth 0cd44d00e1/CMakeLists.txt (L80)
[2] https://cmake.org/cmake/help/git-master/variable/CMAKE_SYSTEM.html#variable:CMAKE_SYSTEM
Signed-off-by: Frank Vanbever <frank.vanbever@mind.be>
Acked-by: Yann E. MORIN <yann.morin.1998@free.fr>
[Peter: update commit message with description from Yann]
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
Some packages test the system name to decide whether to enable/disable
features or link with specific libs.
So we forcefully set the system name form our custom system file, so
that packagses still believe they are running on Linux rather than
Buildroot.
Fixes:
fastd : http://autobuild.buildroot.net/results/f1d/f1dfe90068ad62e733f17a22202235415bda3974/
paho-mqtt-c: http://autobuild.buildroot.net/results/457/457d76279e16247bf58c838a2c5dd0a4f3962c21/
libiio : http://autobuild.buildroot.net/results/281/2812b008a0ab6bab5fe4d45eb9ffe4e9496a8cb4/
and so on...
Reported-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Reported-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: Ben Boeckel <mathstuf@gmail.com>
Cc: Jörg Krause <joerg.krause@embedded.rocks>
Cc: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Cc: Samuel Martin <s.martin49@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
The handling of RPATH in cmake-3.7 has changed drastically, causing a
slew of build failures dues to libraries from the host being pulled in:
- domoticz : http://autobuild.buildroot.org/results/fd0/fd0ba54c7abf973691b39a0ca1bb4e07d749593a/
- freerdp : http://autobuild.buildroot.org/results/5d4/5d429d0e288754a541ee5d8be515454c5fccd28b/
- libcec : http://autobuild.buildroot.org/results/3f3/3f3593bab7734dd274faf5b5690895e9424cbb89/
- and so on...
The bug was reported upstream [0], which dismissed it altogether [1] as
being expected behaviour, quoting:
I don't think there is anything wrong with that change on its own.
It merely exposed some existing behavior in a new case.
Instead, upstream suggested in that same message that a platform
definition be used instead, quoting:
If a toolchain file specifies CMAKE_SYSTEM_NAME such that a custom
`Platform/MySystem.cmake` file is loaded then the latter can set
them as needed for the target platform.
So here we are doing so:
- we add a new platfom definitions that inherits from the Linux one,
then overrides the problematic settings;
- we change our toolchain file to use that platform instead;
- we tell cmake where to find additional modules, so that it can find
our custom platform file.
This has been tested to work in the following conditions:
- pre-installed host cmake, versions 3.5.1 (Ubuntu 16.04) and 3.7.2
(manually built)
- internal cmake, versions 3.6.3 (the current version as of this
patch) and 3.7.2 (with the followup patches).
Thanks to Jörg, Ben and Baruch for the help investigating the issue.
Special thanks to Jörg for handling the discussion with upstream and
pointing to the relevant messages! :-)
[0] http://public.kitware.com/pipermail/cmake/2017-February/064970.html
[1] http://public.kitware.com/pipermail/cmake/2017-February/065063.html
To be noted: Thomas suggested we set these directly in the toolchain
file. Unfortunately, wherever we put those settings in the toolchain
file, this does not work.
Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Jörg Krause <joerg.krause@embedded.rocks>
Cc: Ben Boeckel <mathstuf@gmail.com>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: Samuel Martin <s.martin49@gmail.com>
Cc: Vicente Olivert Riera <Vincent.Riera@imgtec.com>
Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Cc: Peter Korsgaard <peter@korsgaard.com>
Reviewed-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
